1. Field of the Invention
The present invention relates generally to the field of protective coverings for windscreens and, more specifically, to a transparent laminated structure having multiple peel-away film layers for protecting windscreens of rotary aircraft and racing vehicles. The outer film layers have keyed features for aiding in their removal from the underlying film layer.
2. Description of the Related Art
The degradation of aircraft windscreens is a costly problem that also effects safety and mission effectiveness due to distortion of visual and RF electromagnetic wavelengths that pass through a damaged windscreen or sensor window. As such, clarity through aircraft windscreens and sensor windows is imperative for proper operation of an aircraft.
Conventionally, rotary aircraft windscreens and sensor windows are unprotected from environmental damage. As such, the windscreens and sensor windows quickly degrade with scratches and cracks, distorting visible and RF electromagnetic wavelengths that pass there-through. Accordingly, a pilot's or crew member's visibility, his use of night vision goggles, and/or the operation of sensors are impaired which may cause operator error and/or sensor errors, thereby inhibiting mission effectiveness. Additionally, small fissures and defects in the windscreen may be propagated by stress and vibrations during aircraft use, rendering the windscreen entirely unsatisfactory.
The rate of windscreen deterioration is particularly problematic with helicopters, especially those that are performing desert missions since, in addition to blowing sand and debris, the rotor blades of the helicopter and neighboring helicopters can disturb sand and rocks causing a whirlwind of abrasive particles.
Traditionally, various polishes have been used to remove scratches from marred aircraft windscreens. However, the polishing process is not only time consuming, but also may leave swirl marks that dramatically distort the passage of visible and RF electromagnetic wavelengths through the windscreen.
Being that aircraft windscreens are unprotected and the ability to recondition the same is quite limited, aircraft windscreens quickly degrade beyond acceptable standards and require replacement; an expensive and time consuming process.
Although it is know to use multi-layered transparent film in the art of vehicle racing, such as NASCAR®, to extend the useful life of a vehicle's windshield, vehicle windscreens do not face the range of environmental conditions to which aircraft windscreens are subjected. That is, the combination of particulate impacts, rain erosion, wind-shear, arc-over from accumulated precipitation static in the film, light transmission requirements, and film removability without damaging the underlying film layer is unique to application with aircraft.
Accordingly, there is a need in the art for a transparent multi-layered structure having peel-away film layers that is useful in windscreen applications and particularly aircraft windscreen applications. There is also a need in the art for the bonding strength to be sufficient to keep the film layers from delaminating during use, yet be removable as desired without damaging the underlying film or windscreen. A further need is for each film layer to be easily removable, preferably by hand, or with a simple flat edged tool such as a blade. Further yet, there is a need for maintenance personnel to be able to quickly and accurately determine the number of film layers remaining on the windscreen.